my greatest fear for my children was to take them out of an environment that they knew all their life. >> reporter: you tried to prolong the life they knew, as expensive as it was becoming, because you didn't want to hurt them. >> you hit the nail on the head. >> reporter: after using her savings, she couldn't pay her mortgage, and a foreclosure letter soon arrived. >> i opened up the letter and i began to read it. and the whole while, i'm in total disbelief. >> reporter: with her three sons, 15, 16 and 17, darlene faced the prospect of breaking apart her family, because most shelters separate men and women for security reasons. and, advocates say, there are not enough shelters for the new wave of homeless families. >> we had families that were coming in -- >> shawn donovan is secretary of housing and urban development, or hud, which funds homeless programs across the country. what do you say to the families who are living in cars, living in trailers, who have to separate their family to live in a shelter? >> what i would say is they shouldn't have to do that. it's wrong. >> reporter: